Door spring or check



(No Model.)

' H. W. LARSSON. DOOR SPRING 0R 'GH EGK.

Patented Oct. 16, 1894.

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UNITED STATES- PATENT OFFIcn.

HENRY W. LARSSON, OF SPRINGFIELD, MASSACHUSETTS.

DOOR SPRING'OR CHECK.

SPECIFICATION forming part of Letters Patent No. 527,753, datedOctoher16,1894.

Application filed July 13, 1893. Serial No. 480,429. (No model.)

To all whom, it may concern:

Be it known that I, HENRY W. LARssoN, a citizen of the United States ofAmerica, residingin Springfield, Hampden county,-'Mas'- sachusetts, haveinvented new and useful Improve' nents in Door Springs or Checks, ofwhijcli the following is a specification, refereu ce'beinghad to theaccompanying drawings andletters of reference markedthereon. .In thedrawings like letters of reference indicate like parts.

Figure 1 is a plan view of my improved device showing the door closed, apart of the cylinder being broken away. Fig. 2 is a side elevation ofthe same. Fig. 3 is a plan view showing the door open, and Fig. 4c isadetail' view of the spring supporting framef.

In detail a indicates the frame; I), the door;

0, a cylinder supporting bracket mounted on the frame; 01, a springsupporting bracket also mounted on the frame; e,spring;f, plates; f;spring-arms; g,.cylinder barrel; h i, cylinder heads; j, piston;7c,pist0n rod; l, curved extension of piston rod; m, connecting rod; n,a bracket mounted on the door and having one end of the connecting rod mpivotally attached thereto; 0, a cross bar extending between the arms f;p, a pin orpivot between the arms f and having the piston rod extensionZ and the connecting rod m mounted thereon.

The object of my invention is to provide a simple, easily operative andinexpensive device for closing doors gradually; and I accomplish thisobject by the construction herein set out.

The construction and operation of my device are as follows: A suitablespring supporting bracket d is mounted upon the door frame, whichbracket is provided with two wings projecting therefrom. Mountedadjacent to said wings and'preferably next their inner faces are twoplates f provided with extended arms f and having a bar 0 extending fromplate to plate and preferably made integral therewith. A central pivotpin ,1" serves to pivotally connect the plates f with the bracketd andprevents lateral movement while permitting free rotary movement of theplates. A coil spring e is mounted between the plates f and one end ofthe spring engages a engages the cross-bar o, the tension of the springoperating to cause the plates f to ro-j tate on the pivot in adirectionto carry the projected arms of the plates normally toward thecylinder. The connecting'rod m is connected with one of the projectedarmsf preferably by'prov-iding one end of this rod with an opening andpassing the pin 19 through lug g on the bracket 01 while the oppositeendI the same. This attachment I prefer to make v adjacent the outer, faceof the plate, and the A ing of the door, I provide an air-cushion, emi Iploying for that purpose a cylinder barrel g provided with suitableheads, the head h being provided with an opening for the passage of thepistonrod 7c and the head i being closed except for an air vent v, thelatter head be ing pivotally mounted on a bracket 0 which bracket issecured to the door casing.

The pivotal rod p is preferably of the same 'size throughout and isunobstructed between the plates, so that the height of the cylinder maybe varied if desired.

' The device may be used alike on either a right or left hand door asthe connecting rod may be attached with equal ease at eithe side of thespring bracket (1.

In some casesI may attach one of the arms f at the outer face of one ofthebracket wings and theother at the inner face of the other wing, theresult being the same in any event. .I attach the parts in such positionas may appear most convenient for the place where the device is to beemployed.

The curved extension of the piston rod enables ine to carry the pivotalpoint of the connecting rod m,'through which pivotal point and alongwhichrod the force of the spring is transmitted to the door, pastthecenter or pivotal line of the hinge, thus so, changing the location ofthe fulcrum point that the power of the spring will be exerted to holdthe door on a dead center, since the power of ICO the springtransmittedalong the link mpasses almost through the vertical pivotal 'line of thedoor. When however the door is moved a trifle to carry the pivotalpointbeyond the center line then the spring has sufficient power to operateupon the door, and the leverage increases as the door approaches aclosed position, because the line of transmission of force along thelink m becomes more remote from the pivotal axis of the door, andtherefore the leverage of such force about such pivotal axis reaches itsmaximum, and thus the greatest force is exerted at the time when thespring is weakest and when the greatest power is desired. It is also tobe observed that while the length of the piston rod is such comparedwith the length of the arms f and the distance between the brackets thatthe piston will beat right angles to the arms when the door is closed,the length of the arms f constituting thelever through which the forceof the spring is transmitted to the door, is approximately equal to theplay of the piston. Hencethe platesf and piston rod are approximately ina vertical plane with each other when the door is opened to itsfullextent. Inthis positionthe resistance of the cylinderhas its minimumeffect. In fact it is of zero value, and increasesas the door swingsround until it reaches its maximum as the door closes. The utility ofthis arrangement is apparent as it results in economy of time instarting the door to close, with the minimum of concussion, when it isactually closed.

Having, therefore, described my invention,

what I claim, and desire to secure by Letters Patent, is

1. The combination of a door and frame therefor,-brackets on the frameabove the door, a cylinder pivoted on one bracket, a lever pivoted onthe other bracket, a link connecting the end of said lever to the doorand a spring for actuating said lever to close the door, and a pistonworking in the cylinder pivoted at its outer end to the end of thelever, the distance between the brackets, the lengths of the lever andpiston and the play of the piston in the cylinder being so proportionedthat the piston is in line with thelever at one end of its play and atright angles thereto at the other end, substantially as described.

2. The combination of a spring supporting bracket a spring mountedtherein, a spring lever pivotally mounted in said bracket, the

latter comprising two pivotally'mounted arms f rigidly connected, a rodp extending from arm toarm and being of the same diameter throughout, asuitablecheck mechanismconnected with said pin p by a rod Z whichat itsconnecting point with the pin is of lesswi dth than the space betweenthe two arms f whereby the relative position of the severalparts may bevaried substantially as and for the purposes stated.

HENRY W. LARSSON.

Witnesses:

ALLEN WEBSTER, WILLIE E. PETERS.

